The present invention relates to devices capable of generating a wide range of musical-sound waveforms useful in creating or simulating the musical sound of a musical instrument.
Various approaches have been known in the art of generating musical-sound waveforms; they may be classified broadly under (A) analog method and (B) digital method as follows:
(A) Analog Method
(i) Method for synthesizing sine waves generated at various frequencies.
(ii) Method for producing changes in frequency spectrum from pulses or square waves through filters.
(iii) Method for electrically detecting mechanical vibrations of various waveforms.
(B) Digital Method
Instantaneous values of a waveform are digitized and converted into a musical-sound waveform by a D/A converter.
In both analog and digital methods, a large number of control signals are required to obtain substantial variations in the musical-sound wave, resulting in the need for intricate mechanisms. Conversely, with a simple control mechanism, the variety of waveforms available is limited.
According to the method (A)-(i), higher order harmonics, in addition to a fundamental sine wave, must be provided in order to obtain a variety of waveforms. Furthermore, means must be used to control the individual harmonics by controlling the gain of an amplifier or through a resistance voltage-divider in order to control the musical-sound waveform. According to the method (A)-(ii), the kind of waveforms available is limited. The method (A)-(iii) requires the use of various mechanical vibration systems to produce necessary waveforms.
According to the method (B), a computer system having a large memory must be used.
In any prior art method, the mechanism for generating waveforms and means for controlling them are too intricate in construction to vary each waveform instantly and frequently in performing with an electronic musical instrument.